iOS 4.1 Security hole
 

There is a way to "bipass" the security key that you think protects your iphone. If the user knows what they are doing, they can have full access to your phone app, and can view your photos by adding a picture to one of your contacts. This should be fixed in 4.2
iOS 4.1 security bug: bypass passcode entry and access Phone, Photos apps

Re: iOS 4.1 Security hole
 

Password for the iPhone no longer works as it should: IOS 4.1, Apple seems to be opened under a security vulnerability. If you enter a random number in the field of emergency call, then immediately press the button, lock hardware, press the call key, you can access the phone application.